通过命令行输入若干个单词（有重复），输出每个单词出现的频率

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

/**
*@ author ajax_2003
*/
class Base {
public static void main(String[] args ) throws Exception {
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
Map<String, Integer> map = new HashMap<String, Integer>();
String str = null;

while (!(str = in.readLine()).equalsIgnoreCase("quit")) {
System.out.println("请输入数据， 输入quit退出");

if (map.get(str) == null) {
map.put(str, 1);
}
else {
map.put(str, map.get(str) + 1);
}
}
for (Object key : map.keySet().toArray()) {
System.out.println(key + " 出现: " + map.get(key) + " 次");
}
}
}
是这样吧